It appears he may have died in tthis car accident. Sources on the UG say they've confirmed Mask's death here and here. More to come.

From the LA Times:

A bizarre car crash in Newport Beach involving two luxury cars early this morning left one person dead, a second injured, a third arrested for gross vehicular manslaughter and a fourth person was detained by police long enough to sober up.

A Newport Beach Police Department officer allegedly witnessed the wreck and saw a red Ferrari and a white Porsche "spinning out of control" on Jamboree Road between Bison Avenue and East Bluff Drive at 12:57 a.m., Newport Beach Lt. Craig Fox said. The Ferrari "hit the curb and then collided with a pole." The Porsche came to a stop at the scene for a few seconds and then sped away, Fox said.

"It was terrible. It was extensive damage to the vehicle," Fox said, adding that the Ferrari appeared to have split in half.

An unidentified man in the Ferrari was pronounced dead. A woman in the car was ejected during the accident and taken to a hospital, where she was in stable condition, Fox said. He said police have not yet determined which one was driving and which one was the passenger.